Sack sewing machine



Dec. 3, 1935. EBERT 2,023,316

SACK SEWING MACHINE Filed July 3, 1930 9 Sheets-Sheet 1 Dec. 3, 1935. F.EBERT SACK SEWING MACHINE Filed July 3, 1930 9 Sheets-Sheet 2 w w n 5 HQ3, 1935. F. EBERT SACK SEWING MACHINE Filed July 3, 1930 9 Sheets-Sheet3 Dec. 3, 1935. F. EBERT 2,023,316

SACK SEWING MACHINE lzpvenfar':

Dec. 3, 1935. EBERT 2,023,316

SACK SEWING MACHINE Filed July 5, 1950 9 Sheets-Sheet 5 a? a5 a: 15

Dec. 3, 1935. EBERT 2,023,316

SACK SEWING MACHINE Filed July 3, 1930 9 Sheets-Sheet 6 Dec. 3, 1935. F.EBERT 2,023,315

SACK SEWING MACHINE Filed July 3, 1930 9 Sheets-Sheet 7 Dec. 3, 1935.EBERT SACK SEWING MACHI 9 Sheets-Sheet 8 Filed July 3, 1930 Dec. 3,1935. F. EBERT SACK SEWING MACHINE Filed July 5, 1930 9 Sheets-Sheet 9Ll/Zn fdr:

l nk; fjerf Patented Dec. 3, 1935 UNITED STATES PATENT OFFICEApplication July 3, 1 In Germany 930, Serial No. 465,729

July 13, 1929 16 Claims. (Cl. 112-162) The present invention relates toa sack sewing machine, and particularly to large and heavy typesembodying novel features to permit operation at a much higher speed thanis possible now. This effect is produced, above all, by a new and.extraordinarily stable drive of the loopers, which eliminates the usualtransmission by means of rods lacking in stableness and vibrating athigh speed operation or of toothed segments.

According to the invention, the drive of the thread-carrying lowerthread looper constitutes a self-contained unit which can bemanufactured separately and attached to the machine as a whole.Moreover, the device can be turned about a vertical axis and adjusted sothat the lower thread is brought safely in front of the needle and arapid change from narrow to broad seams or vice versa can be effected.

The drive of the lower thread looper contains an articulated connectionby means of which the looper is held to its front end position until theneedle ascends again and the needle loop has opened, which insures theproper formation of stitches. The length of time during which the looperis kept idle can be regulated by adjusting the driving lever. The looperlever itself permits of axial and torsional displacement, it beingfixably positioned on the boss of a driven intermediate lever. Thisadjustability is of particular importance when needles of differentsizes and thicknesses are employed.

Furthermore, the lower thread is regulated by the vertically oscillatinglooper lever, whereby a much finer adjustment is attained than byemploying rotary regulators of the usual type. For this purpose, aprojecting arm of the looper lever, which cooperates in the latterspendulumlike motion, is provided with a thread-receiving eye cooperatingwith two stationary eyes which can be adjusted independently of theoscillating eye.

The lower thread looper is provided on its back with a rib over whichpasses the needle thread loop on the looper while the other looperthread is positioned in the groove-like indentation above the rib, thetwo threads being thus prevented from coming into contact with oneanother or the friction being at least reduced to a considerable extentso that breakage of thread due to friction is eliminated and a poorerquality of thread can be worked.

The ordinary looper moving over the table of the machine is of veryrigid construction also. It is driven directly from the main shaft ofthe machine and from the end where the stitch-forming devices arelocated. A crank serves as a driving means which is arranged on theshaft and actuates directly, by means of a-ball-joint and a lever, thelooper lever disposed axially and torsionally displaceable on the bossof this lever. This construction eliminates not only the usual lessstable connecting rods, but reduces also the number of turning points toa minimum, which contributes to a considerable increase in speed.

The auxiliary looper required for sewing with two threads and adapted tohold the looper thread until the pull of the needle loop has taken placeis driven directly from the lever of the looper moving over the table,the arrangement being such as to make the entire driving mechanism ofthe main loopers readily accessible.

Provision has finally been made to sew with two or three threads on thesame machine. For this purpose the auxiliary looper with drive can beremoved and replaced by a fixed thread guide cooperating with a threadeye arranged on the oscillating lever of the looper moving over thetable, whereby the second lower thread is regulated by the motion of itsown looper.

One embodiment of the invention is illustrated in the accompanyingdrawings, in which Figure 1 is a front view of the sewing machine,partly in section; Figs. 2 and 3 are, respectively, an enlarged frontand top view of the looper driving devices showing the machine operatingas a twothread machine; Fig. 4 is a top view of the lower thread looperdrive forming a self-container unit; Fig. 5, a front view of the lowerthread looper with drive and feeder; Fig. 6, a sectional side view ofone of the fixed eyes for the lower thread and of the adjusting deviceof the lower thread looper unit; Figs. 7 and 8 are, respectively, a sideview and cross section of the lower thread looper with needle threadloop; Fig. 9 is a top view, partly in axial section, of the entirelooper and auxiliary looper arrangement; Fig. 10, a side view,particularly of the auxiliary looper; Figs. 11 and 12 are, respectively,a top and front view of the looper arrangement and drive if the machineis used as a three-thread machine; Figs. 13 to 16 show progressively,seen from the front, the production of a two-thread seam; Figs. 17 and18 are, respectively, top and bottom views of this seam; Fig. 19 is atop view of the loopers at work; Figs. 20 to 22 show progressively, seenfrom the front, the production of a three-thread seam; Fig. 23 is adiagram thereof; Fig. 24, a side view of Fig. 20; and Fig. 25, a topview of the loopers at work.

Referring to the drawings, the sewing ma- 5 chine according to theinvention is driven in the usual manner by a main shaft I extendinghorizontally in the lower portion of the frame 2 from one side to theother. The seam is produced in the known way by the needle 3 and the twoloopers 4 and 5.

The lower thread looper 4 forms with its drive a self-contained unit(Fig. 4) and is disposed in a bracket 3 secured to the base plate 1 ofthe machine. The rotation of the main shaft l, by means of an eccentrichaving a spherical surface, a guide fork 3 and a ball pivot I0, istransmitted first to a vertically oscillating driving lever l l whichoscillates with its long bush-like boss l2 about an axis l3 (Figs. 3, 4and 5) fixed in the bracket 4. To the boss l2 a lever arm I4 is clampedby means of the screws l5 disposed in the gripping jaws ii of theradially split boss ll of the arm l4 which can be laterally displaced orturned after the screws l5 are loosened.

The lever arm I4 is connected by a joint IS with an interposed lever I9which, with its long bush-like boss 20, oscillates about an axis 2| ofthe lower thread looper 4 also positioned in the bracket 6.

. The lower thread looper 4, with its lever 22, is secured axiallydlsplaceable and rotatable to the boss 23 of the intermediate lever I 9.The boss of the lever contains for this purpose a radial gap clampedremovably, by means of screws and gripping jaws, to the boss 20 of theintermediate lever I9 in the same manner as the lever arm l4 to the bossl2 of the driving lever H.

Owing to the articulated drive l4, I8, IS, the lower thread looper 4,after its advance, stands still until the needle 3 moves up again andthe needle loop has opened, the duration of this stoppage being capableof variation by adjusting the lever arm H. The regulation of the lowerthread 23 takes place from the lower thread looper lever 22, the arm 24of which is disposed on the other side of the lever 22, being providedfor this purpose (Fig. 5) with a thread eye 25 which cooperates in theoscillation of the lever, is adjustable and can be set as to height inthe arm 24 and fixed by a. screw 26.

The thread eye 25 cooperates with two stationary thread eyes 21 disposedon both sides of its path and secured by a common base plate 28 to thebracket 6. These eyes 21 can also be adjusted as to height (Fig. 6), andthe base plate 23 contains for this purpose a longitudinal slot 33 topermit the passage of the fastening screw 23.

To prevent-the lower thread 23 from coming in frictional contact withthe needle thread loop 3| disposed transversely to it, the back of thelower thread looper 4 is fitted with a rib 32 (Figs. 7 and 8) whichkeeps the loop 3| from touching the lower thread 23 moving in the groovelocated above the rib 32.

The entire mechanism of the lower thread looper 4 can be turned about avertical axis and adjusted so that the lower thread 23 is brought safelyin front of the needle 3 and rapid adjustment to various thicknesses ofthe needle can be effected. For this purpose, the pin 33 (Fig. 9)passing through the base plate 1 of the machine frame 2 serves as axisof rotation for the bracket 6, the adjustment taking place by means ofthe two screws 34 which can be tightened from below and pass through theslots 35 of the base plate I, the slots being curved about the pin 33(Fig. 6).

The looper 5 moving over the table 36 is driven directly from the end ofthe main shaft l positioned near the stitch-forming device (Fig. 11).For this purpose, the end of the shaft carries a crank 31 which. bymeans of a connecting rod 38 and the ball pivots 89, moves the drivinglever 5 4| up and down thereby oscillatingly rotating it about thelooper axis 40. The lever 4| is provided with a bush-like boss 42 forswinging about the axis 40, the boss being firmly positioned in the eyes43 of the base plate I; To the 10 boss 42 is clamped the lever 44holding the looper 5 and having a radially split boss 45, the fixingbeing effected by means of the jaws 46 and the screws 41. After thescrews 47 have been loosened the lever 44 can be axially displaced as 15well as turned.

If the machine is used as a two-thread machine, as shown in Figs. 2 and3, an auxiliary looper is used (Fig. 10) which with its axial shank islocated in the center of its axis 49 os- 20 cillatingly rotating in thebosses 50 of a carrier 5i and thus turning oscillatingly the auxiliarylooper 48. It is driven directly from the looper lever 44 by means of aconnecting-rod 52 engaging the back of the lever 44 and being connected25 with the lever 53 located on the looper axis 49. The balls 54 serveas the connection. The carrier 5i is secured on top to the boss 55 ofthe main shaft l slightly below the table 36.

All parts below the table 36 are thus freely 30 accessible.

In order to sew on the same machine with three threads, provision hasbeen made to replace the auxiliary looper device by a thread guide forthe third thread es. 215' For this purpose, the carrier 5! together withthe entire auxiliary looper device (Fig. 11) can be taken off owing tothe fact that the attachment is removably secured, for instance by thescrews 51. Moreover, a carrier 58 is provided 40 which is constructed sothat it can be secured in working position in lieu of the member 5|. Thecarrier 58 possesses two stationary thread eyes 59 disposed on bothsides of the path of a thread eye 60 arranged on the looper lever 44 andcon- 45 sequently adapted to swing up and down. This eye 60 may bepermanently attached to the lever 44 or fitted to it only when threethreads are used in working.

Figs. l3-19 show the formation of the stitch 50 of a two-thread sewingmachine and Figs. 20-25 show the formation of the stitch of athreethread sewing machine.

Fig. 13 shows in front view the link side end position of the looper 5.The needle 3 travels 55 downwards from this position and penetrates intothread triangle carried up by the looper 5 as shown in Figs. 14 and 17.

The looper 5 swings immediately back and fills the thread triangle. Alsothe looper 4 will swing back (to the left) and permits thereby theneedle thread knot to finally fall.

Fig. 17 shows the position in top plan view of the various parts shownin Fig. 13 together with the seam, the last thread triangle being fromthe top. Fig. 18 shows the seam from the bottom.

Fig. 14 shows the needle in its deepest position, whereby the looper 5still swings back somewhat while the looper 4 now moves against theneedle and will enter in its thread knot, when it moves upwardly.

Now the looper 5 will also swing forward, that is, against the looper 4which swings still further outwardly and will take off the thread bymeans of a point as shown in Fig. 15. This thread is taken upwardly asshown in Fig. 16, so that the cycle can be repeated in that the threadtriangle is again built up.

Fig. 19 is a top view of Fig. 15.

The auxiliary looper 48 holds the looper thread 23 as shown in Fig. 15and as already described it holds it so long until the needle thread hasbeen pulled.

The positions of the various elements of Figs. 20-25 correspond exactlyto Figs. 13-19. The looper 5 is merely replaced by a thread guidinglooper and the auxiliary looper is removed therefrom.

From the figures it is apparent that in a three thread scam the threadof the gripper 5 is brought to the needle instead of to the thread ofthe looper 4 as in a two thread seam. The needle then penetrates throughthe loop of the looper thread while the looper thread of the looper 4 issecured on the edge of the material as seen in Figs. 21 and 23.

I claim:-

1. In a sewing machine of the type described, means whereby said machinemay be converted at will to sew with two threads or with three threads,comprising a removable auxilary looper unit to permit sewing with twothreads and a thread guide adapted to replace the said auxiliary looperunit to permit sewing with three threads.

2. In a convertible sewing machine according to claim 1, a table, a mainshaft, a stitch-forming device, a bearing for the main shaft arrangedoutside the stitch-forming device, a drive therefor, and acarrieradapted to support the said auxiliary looper and its drive and removablysecured below the table to the said bearing.

3. In a convertible sewing machine according -to claim 1, a table, alooper adapted to move thereover, a vertically oscillating arm formingpart of the said looper, a thread eye disposed on the said arm, anexchangeable thread guide adapted to replace the said unit to permitsewing with three threads and consisting of a carrier and two threadeyes fixed thereto, the said stationary thread eyes being disposed onboth sides of the said vertically oscillating thread eye.

4. An overcast seam sewing machine for sacks, carpets and bed covers,having an upper and a lower looper, a base plate, a longitudinallyextending main drive shaft, a lower looper arrangement driven thereby,and including a thread regulating means, and a support carrying thelower looper, said support being secured to the said base plate of themachine so as to be capable of being rotatable and adjustable about avertical axis.

5. A sewing machine in accordance with claim 4, including also anintermediate lever, and an intermediate shaft, the lower looper beingcontrolled by said intermediate lever by means of said intermediateshaft, means whereby said intermediate lever may be adjusted axially, aswell as by rotation about its shaft, and secured, and means whereby saidlower looper may be adjust able laterally and also rotatably about itsaxis.

6. A sewing machine in accordance with claim 4, including also anintermediate lever, and an intermediate shaft, the lower looper beingcontrolled by said intermediate lever by means of said intermediateshaft, means whereby said intermediate lever may be adjusted axially, aswell as by rotation about its shaft, and secured, and means whereby saidlower looper may be adjustable laterally and also .rotatably about itsaxis, said means comprising levers having hubs upon which the adjustingelements are mounted. I

7. A sewing machine in accordance with claim 4, wherein an auxiliarylooper is provided for sewing with two threads, said looper beingremovable as a whole together with its drive means and its support, andreplaceable by a thread 10 guide which permits sewing with threethreads.

8. A sewing machine in accordance with claim 4, wherein an auxiliarylooper together with its drive means is mounted upon a block which isremovably secured below the table plate upon 15 the support of the mainshaft, lying at the outer side of the stitch-forming means.

9. A sewing machine in accordance with claim 4, wherein an auxiliarylooper is provided which has a rounded acute angled configuration at its20 knee.

10. A sewing machine in accordance with claim 4, wherein a thread guideis provided which is exchangeable for an auxiliary looper means forsewing with three threads, and consists of two 25 stationary threadeyelets mounted upon a block, a thread eyelet mounted upon a looper,which swings over the table plate, said stationary eyelets beingarranged on both sides of said movable thread eyelet and on both sidesof a lever which swings up and down.

11. In a convertible sewing machine according to claim 1, a table, aconnecting rod, an arm arranged on the axis of the auxiliary looperunit, a looper moving over the said table, and an arm forming part ofthe said looper and adapted to drive directly the said auxiliary looperunit by means of the said connecting rod. I

12. A sewing machine in accordance with claim 4, in which a lower looperlever and an arm are 40 provided and the arm extending from the lowerlooper lever, a thread receiving eyelet for the lower thread arrangedupon said arm, said eyelet having an axis of rotation, and means wherebysaid eyelet is capable of adjustment with respect 45 to its axis ofrotation.

13. A sewing machine in accordance with claim 4, wherein stationarythread eyelets and a swinging thread receiving eyelet are provided, thestationary eyelets being provided on each side of 50 the swinging threadreceiving eyelet in order to regulate the lower looper thread, and meanswhereby said stationary eyelets are capable of adjustment up and down.

14. A sewing machine in accordance with claim 55 4, wherein the lowerlooper has a longitudinally extending rib defining a groove arrangedlaterally of the looper over which travels the needlethread loop formedin sewing, while one strand of the looper thread passes through thegroove 60 defined by the rib.

15. A'sewing machine in accordance with claim 4, comprising a looperlever for the upper looper and having a driving lever, said drivinglever having a hub, and said looper lever being rotatably c5 andlaterally adjustable upon the said hub.

16. A sewing machine in accordance with claim 4, in which an auxiliarylooper, and a push rod are provided, the auxiliary looper being drivendirectly by the push rod.

FRITZ EBERT.

